Gastight box



G. R. BLUEM GASTIGHT BOX Jan. 10, 1967 Filed May 20, 1965 2 Sheets-Sheet 1 FIG. 5

INVENTOR. GA RY R. 81. UEM

e BM A r TORNEYJ' Jan. 10, 1967 G. R. BLUEM 3,297,229

GASTIGHT BOX Filed May 20, 1965 2 Sheets-Sheet. Z

BY M 560 A TTORNE YJ United States Patent Oflice 3,297,229 Patented Jan. 10, 1967 3,297,229 GASTIGHT BOX Gary R. Bluem, Minneapoiis, Minn, assignor to Possis Machine Corporation, Minneapolis, Minn, a corporation of Minnesota Filed May 20, 1965, Ser. No. 457,358 Claims. (Cl. 229-37) This invention is a gastight box closure and a method for making a box closure gastight. More particularly this invention relates to a method of applying beads of adhesive in such a configuration to flap closure boxes that when the flaps are folded in, a gastight seal will result.

The sealing of the box opening is accomplished by laying beads of gastight, non-porous adhesive along flap edges that will be exposed to the surrounding atmosphere when the box is closed. These beads are also placed so near the corners where the flaps come together that some of the adhesive is exuded over the corners when the flaps are folded in over the box opening. Any appropriate adhesive that is non-porous and will exude when compressed and which will set to a gas impervious seal when the box is closed may be employed. Natural and artificial rubber cements, and various thermoplastic compositions known in the trade as hot-melts are good examples of suitable materials from which to form the adhesive beads.

Packagers of hygroscopic materials have tried many different ways to protect their products Within boxes that are gastight to keep water vapor carrying air from their products. There have been and are many such gastight packages, but they have not been entirely satisfactory for all uses. One common drawback to gastight packaging known herebefore is the difiiculty encountered in using it in high production package filling equipment. Other techniques for making packages gastight are not permitted with food products, are too expensive for some applications and so on. Thus, it is an object of this invention to provide a box which includes a gastight closure.

It is another object of this invention to provide a method for applying adhesive and sealing the flaps on a standard box of gas impervious material to provide a gastight seal.

Yet another object of this invention is to provide a gastight box closure well adapted to automatic filling and closing machinery.

It is still another object of this invention to provide a method for depositing adhesive on the flaps of a standard box constructed of gas impervious material so that the adhesive may be applied mechanically with straight passes of the box beneath adhesive depositing means.

It is yet still another object of this invention to provide a method of applying adhesive to a box blank of gas impervious material which may then be folded into a gastight container.

A further object of this invention is to provide a method of sealing the closure of a box made of gas impervious material by means of beads of flowable, setting, adhesive material in such quantity and location as to cause the closing of the flaps to adhere them to one another and exude the adhesive over the corners between flaps and thus close all avenues of entrance for gas into the interior of the box.

Other and further objects of the invention are those in-' being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The invention will be described with reference to the drawings in which corresponding numerals refer to the same parts and in which:

FIGURE 1 is a perspective view of a box with four flaps, two folded inwardly and two folded outwardly and adhesive beads applied;

FIGURE 2 is a perspective view of the box of FIGURE 1 with one of the previously open flaps folded inwardly;

FIGURE 3 is a perspective view of the box of FIGURE 2 with the additional adhesive bead being placed on the remaining unfolded flap;

FIGURE 4 is a perspective view of the box of FIGURE 3 with the flaps folded into an airtight closure;

FIGURE 5 depicts a partial elevation showing the closure of FIGURE 4 and is drawn to a larger scale than FIGURE 4;

FIGURE 6 depicts a box blank and the adhesive pattern upon which the adhesive is placed to accomplish an airtight closure; it is drawn to the scale of FIGURES 1-4; broken lines represent hidden adhesive and fold lines;

FIGURE 7 depicts the box resulting from folding the box blank of FIGURE 6 and drawn to the scale of that figure.

Referring now to the drawings and particularly to FIGURE 1 a box 10 is of a well known type having a rectangular transverse cross section and composed of four sides. The box It) has sides 12 and 14, which are opposing sides, and the adjacent sides 16 and 18. Each side has end flaps the full width of the sides. Of course, the box material must be of a gas impervious type such as treated or coated chip board which is well known.

Sides 12, 14, 16 and 18 are provided with corresponding flaps 20, 22, 24 and 26 hingedly secured thereto along corresponding fold lines 32, 38, 34 and 48. Notice that the flaps 24 and 26 have a width dimension which is substantially less that the width of the sides 12 and 14. Flaps 20 and 22 are of a width approximately the same as the sides 16 and 18. While the fiaps need not be exactly as shown, at least two opposed flaps must be of a width sufficient to cause them to overlap each other when folded in over the box opening. Between the flaps are the corners which along with the flaps surfaces are potential points at which gases such as air and water vapor could enter box 10 unless prevented from doing so.

To accomplish a gastight seal for the box as described, a bead of adhesive which is flowable and settable as well as being non-porous and, therefore, gastight and exuding upon being squeezed together between two flaps is deposited on the box flaps, A commonly used class of adhesive which meets the qualifications is non-porous thermoplastic known in the trade as hot-melt. Other adhesives that might serve are rubber cements and other plastics that are either temperature or solvent softenable to an exuding consistency. A bead 27 is deposited, in FIGURE 1, at the outermost corner 28 of the flap 20, and run inwardly from the point 28, towards the box along the edge 30 perpendicular to the folding line 32. It will be noted that the fiaps 24 and 26 have been previously folded inwardly so as to form, with the flaps 20 and 22, a substantially fiat plane. Such configuration facilitates the box 1i) being passed, by a straight line conveyor, below an adhesive nozzle which is conveniently employed to deposit adhesive on the flaps. The bead 27 is continued across the flap 24 parallel, and in close proximity, to the folding line 34. From the flap 24 the bead 27 continues outwardly from the box along the edge 36 of the flap 22, perpendicular to the folding line 38 to the outermost corner 40. Similarly, head 42 is deposited on the box from the corner 44 of the flap 20 inwardly along the edge 46 perpendicular to the folding line 32, across the flap 26, in close proximity and parallel to the folding line 48. Bead 42 is continued outwardly from the box along the edge 50, perpendicular to the folding line 38 of the fiap 22 to the corner 52. The beads 27 and 42, as deposited, should be of suflicient diameter and softness to spread and exude when compressed between the flaps.

In FIGURE 2 the flap 22 has been folded inwardly and pressed into adhesive engagement with the flaps 24 and 26. When this is done, it will be noted that the exudable beads 27 and 42 have, over a portion of their lengths, been turned upon themselves to form beads of double thickness. When pressed together, they amalgamate to become one bead. These double beads are also the preferred arrangement to assure sufiicient bead material to cover the corners of the closure to seal them.

FIGURE 3 shows a third continuous adhesive bead 54 deposited on the flap 20 of box from the corner 44 to the corner 28. Bead 54 connects the beads 27 and 42. To deposit bead 54 on the flap on a straight line conveyor, box 10 is rotated 90 on the conveyor which carries the box below a nozzle that deposits the bead. It will be noted that the three beads 27, 42 and 54 are joined at the corners 28 and 44 to form one continuous head.

The flap 20 is, as seen in FIGURE 4, folded over onto the unit to perfect the airtight seal. To perfect the seal it is necessary to press the flaps together to exude adhesive over the corners of the box. The adhesive beads 27, 42 and 54 are of such mass and softness that adhesive material is readily exuded over the corners to fully seal the box 10.

In FIGURE 5 a View of the completed seal is seen and it is evident that the composite adhesive bead, made up of the adhesive beads 27, 42 and 54, forms one continuous head which acts as a gasket as well as an adhesive when the flaps are folded in the manner described.

The closure described above is a very convenient mode for despositing the adhesive during straight line passes below adhesive dispensing nozzles, but it is also possible to deposit various forms of adhesive on a flat box blank as is depicted in FIGURE 6. Later when the box is to be placed in use, the blank is then folded into box form and the adhesive softened by a suitable solvent or temperature. The side seam and one end are secured, the box filled and it is finally closed by folding the top flaps as described above. This causes the preplaced softened adhesive to seal the box as set forth in the description of the closure.

In FIGURE 6, the box blank 60 comprises a series of generally rectangular portions numbered 62, 64, 70 and 72 which are the sides of the box when folded appropriately. Numbers 66, 68 and 74 designate the fold lines between the box sides. A side seam flap 76 is hinged along fold line 78 to portion 62. Flap 76 is the usual way to provide overlap between the marginal sides of the blank when formed into a box.

Rectangular portion 62 is provided with two foldably secured closure flaps 80 and 82. They are hinged to rectangular portion 62 at the folding lines 81 and 83 respectively. Rectangular portion 64 is provided with simi lar flaps 84 and 86 foldably secured thereto at the folding lines 88 and 90 respectively. A third pair of flaps 94,

and 96 are foldably secured to rectangular portion 70 at the folding lines 98 and 100 respectively. Flaps 102 and 104 are foldably secured to the fourth rectangular portion 72 about the fold lines 106 and 108 respectively. All the flaps have one dimension substantially the same as the edge of the rectangular portion to which they are secured. Flaps 80, 82, 94 and 96 have a second dimension sufficient to overlap when folded, here shown as about the width of the rectangular portions 64 and 72.

Adhesive is deposited on the flaps as shown by the solid and broken parallel lines. As shown in FIGURE 6, the side of the blank 60 that will ultimately be the inside of the box is shown. Broken lines show adhesive on the back side and solid lines on the front of the blank as shown.

On the reverse side of the side seam flap 76, at least one head of adhesive 110 is deposited in a continuous bead, the length of the flap. If only one bead is used, it should be placed near fold line 78 as shown.

A bead of adhesive 112 is provided on the flap following the free periphery on the front side of the flap, but excluding the edge by the fold line. Beads of adhesive 113 and 114 are applied to the front side of the flap 82 as shown.

A bead of adhesive 116 is deposited on the reverse side of the flap 84 in close proximity and parallel to the folding line 88. A similar bead of adhesive 128 is provided on the reverse side of the flap 102 in close proximity and parallel to the folding line 106.

On the flap 94, two beads of adhesive 120 and 122 are deposited, one on each of the edges perpendicular to the folding line 98 on the front side of the flap. Beads of adhesive 124 and 126, corresponding to the beads of adhesive 120 and 122, are to be applied to the front side of the flap 96 along the edges perpendicular to the folding line 100. As a variation in the pattern shown on flaps 80 and 94, there is no bead on flap 82 connecting beads 113 and 114. Instead a bead 101 is placed on the reverse side of the flap 96 parallel and near fold line 100.

On the reverse side of the flap 86 is deposited a bead of adhesive 118 in close proximity and parallel to the folding line 90. A bead of adhesive 130 is applied to the reverse side of flap 104 in close proximity and parallel to folding line 108.

To fold the box blank 60 into an airtight container, the procedure is to first fold outwardly, in FIGURE 6, the flap 76 along the fold line 78. The second rectangular portion 64 is then folded outwardly from the rectangular portion 62 along the folding line 66 to a position perpendicular to the rectangular portion 62. The third rectangular portion 70 is then folded to the left in FIGURE 6, along the fold line 68, to a position parallel to the rectangular portion 62. Finally the box shell is completed by folding the rectangular portion 72 about the folding line 74 parallel to the rectangular portion 64 to engage the rectangular portion 62 and the flap 76. The flap 76 is then pressed to the rectangular portion 72 and bead secures the rectangular portions 62 and 72 adjacent to each other forming a rectangular tube.

The flaps 86 and 104 are folded inwardly, toward the center of the box. Next the flap 96 is forced into adhesive engagement with the flaps 86 and 104. Flap 82 is then folded in to complete the bottom of box 60. The bottom flaps are pressed sufficiently to cause the beads between flaps 82, 86, 96 and 104 to exude over the bottom corners of the box.

After the box is filled, flaps 84 and 102 are folded inwardly. Flap 94 then pressed in so that beads and 122 engage beads 116 and 128 respectively. Finally flap 80 is pressed closed to cause bead 112 to engage adhesively three sides of flap 94.

Although the patterns as laid on the blank are different for flaps 82 and 96 as compared to flaps 80 and 94, the end result is the same. In both cases there is a continuous bead acting as a gasket following a tortuous path between all fiap edges that are exposed to the surrounding atmosphere. While only two different patterns that achieve this end are shown, it is clear that any pattern which produces this tortuous gasket effect is sufficient to seal the edges of the flaps. It is possible to omit the beads 116 and 128 on flaps 84 and 102 and rely on beads 120 and 122 on flap 94 to seal between flap 94 and the two fiaps 84 and 102. The main advantage of the double beads or beads engaging each other is to assure corner coverage. In all cases, sufiicient adhesive should be used to provide for material to exude over the box corners from the beads nearest them. This corner covering is shown at 130 and 132 in FIGURES 2, 3, 4 and 5 FIGURES 4 and 5 show how the beads ultimately form the continuous seal or gasket following the tortuous path extending between all flap edges where gas could otherwise enter the box.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

What is claimed is:

1. A blank for constructing an airtight box comprising:

(1) a fiat sheet of non-porous material having;

(a) a first rectangular portion (b) a second rectangular portion hinged to said first rectangular portion along a fold line defining adjacent edges of said rectangular portions;

(0) a third rectangular portion similarly hinged to said second rectangular portion;

(d) a fourth rectangular portion similarly hinged to said third rectangular portion; the first and third portions being substantially alike and the second and fourth portions being substantially alike;

(e) a first pair of flaps, each of which shares a common foldline edge with one edge of said first rectangular portion;

(f) a second pair of flaps each of which is foldably secured to said second rectangular portion along an edge and each of said second pair of fiaps having a length which is the same as the width of said second rectangular portion;

(g) a third pair of fiaps each of which is foldably secured to said third rectangular portion along an edge and each of said third pair of flaps having a length which is the same as the width of said third rectangular portion;

(h) a fourth pair of flaps each of which is foldably secured to said fourth rectangular portion along an edge and each of said fourth pair of flaps having a length which is the same as the width of said fourth rectangular portion;

(i) an end flap foldably secured to said first rectangular portion along the edge corresponding and opposite to the edge shared with said second rectangular portion;

(j) said blank being foldable into a rectangular tube with said end flap overlapping a part of said fourth rectangular portion and opposed flaps folded inward at each end of said tube to close the ends thereof;

(2) and beads of non-porous adhesive placed on said blank so that every flap edge that would otherwise be exposed to the surrounding atmosphere and is adjacent another fiap edge will be secured to said other flap edge by said adhesive; said adhesive being placed on said blank in such quantity adjacent the corners thereof that when said blank is folded into a box, some of the adhesive is exuded over the box corners.

2. The blank defined in claim 1 wherein said first and third rectangular portions are larger than said second and fourth portions.

3. The blank defined in claim 1 where said first pair of flaps have a width which is the same as the width of second rectangular portion.

4. The blank defined in claim 1 wherein said first pair and third pair of flaps each have a width which is the same as the width of the second rectangular portion.

5. The blank defined in claim 1 wherein said adhesive heads have such dimensions and softness to facilitate substantial exuding when pressed.

References Cited by the Examiner UNITED STATES PATENTS 1,976,980 10/1934 Bergstein.

2,411,622 11/1946 Guyer et al 22937 X 3,007,376 11/1961 Hickin et al. 93-36 3,018,701 l/1962 Keely 9336 3,097,574 7/1963 Kuchenbecker 93-36 3,097,783 7/1963 Burt et al. 22937 3,140,809 7/1964 Hickin et al 22937 3,166,231 1/1965 Hickin et al 22937 3,184,144 5/1965 Green et al 22937 3,194,473 7/ 1965 Rumberger 22937 GEORGE O. RALSTON, Primary Examiner.

JOSEPH R. LECLAIR, Examiner.

D. T. MOORHEAD, Assistant Examiner. 

1. A BLANK FOR CONSTRUCTING AN AIRTIGHT BOX COMPRISING: (1) A FLAT SHEET OF NON-POROUS MATERIAL HAVING; (A) A FIRST RECTANGULAR PORTION (B) A SECOND RECTANGULAR PORTION HINGED TO SAID FIRST RECTANGULAR PORTION ALONG A FOLD LINE DEFINING ADJACENT EDGES OF SAID RECTANGULAR PORTIONS; (C) A THIRD RECTANGULAR PORTION SIMILARLY HINGED TO SAID SECOND RECTANGULAR PORTION; (D) A FOURTH RECTANGULAR PORTION SIMILARLY HINGED TO SAID THIRD RECTANGULAR PORTION; THE FIRST AND THIRD PORTIONS BEING SUBSTANTIALLY ALIKE AND THE SECOND AND FOURTH PORTIONS BEING SUBSTANTIALLY ALIKE; (E) A FIRST PAIR OF FLAPS, EACH OF WHICH SHARES A COMMON FOLDLINE EDGE WITH ONE EDGE OF SAID FIRST RECTANGULAR PORTION; (F) A SECOND PAIR OF FLAPS EACH OF WHICH IS FOLDABLY SECURED TO SAID SECOND RECTANGULAR PORTION ALONG AN EDGE AND EACH OF SAID SECOND PAIR OF FLAPS HAVING A LENGTH WHICH IS THE SAME AS THE WIDTH OF SAID SECOND RECTANGULAR PORTION; (G) A THIRD PAIR OF FLAPS EACH OF WHICH IS FOLDABLY SECURED TO SAID THIRD RECTANGULAR PORTION ALONG AN EDGE AND EACH OF SAID THIRD PAIR OF FLAPS HAVING A LENGTH WHICH IS THE SAME AS THE WIDTH OF SAID THIRD RECTANGULAR PORTION; 